The fuel control actuator, sometimes called the FCA or MPROP, controls how much fuel the high-pressure pump delivers to the rail, and a failing one causes pressure faults and stalling.
What it does
On common-rail diesels a fuel control actuator on the injection pump regulates rail pressure by metering fuel into the pumping elements. The computer commands it to hold precise rail pressure. When it sticks or fails, rail pressure becomes erratic.
Signs it is failing
- Rail-pressure fault codes
- Stalling, surging, or hard starting
- Power loss under load
- Erratic rail pressure on a scan tool
Replacement and what to know
A failed fuel control actuator is replaced, and the fuel supply and filters are checked since contamination can affect it. Confirm the actuator is the cause rather than a supply problem or a leaking injector before replacing it.
Frequently asked questions
What does the fuel control actuator do?
It meters fuel into the high-pressure pump to control rail pressure, holding the precise pressure the computer commands.
What are signs it is failing?
Rail-pressure codes, stalling or surging, hard starting, and erratic rail pressure on a scan tool.
Is it the actuator or the pump?
Confirm with rail-pressure data and rule out supply problems and leaking injectors before replacing the actuator.
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